OK, not worth the hassle..
Also would doing this be illegal?
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Yes, that would essentially be stealing a license for a program you don't already own.
You may transfer an existing program from one computer to another, providing that you remove it from the source machine first. To do that, you would simply uninstall it from the source machine and then use your original media to install it on the destination machine. If you lost the media or if you downloaded it directly from Adobe and don't have the original distribution, you'll need to contact Adobe for details on how to obtain replacement media.
There have been a number of mentions on this thread about software piracy (i.e. downloading software from Torrents or other P2P clients). This would constitute illegal activity, discussion of which is prohibited here.
The bottom line is that if you didn't purchase the software, you have no legal rights to use it, regardless of how it was obtained.
With that said, there are free alternatives like
The Gimp that are very similar to Photoshop in terms of functionality.